How many days did the pilgrimage talked about in The Canterbury Tales usually take?
Unfortunately, there is no "usual" because each pilgrim in Chaucer's pilgrimage of tales began from a different location. It was a fluke that the pilgrims all happened upon the inn at the same time and decided to continue together. But the distance from the inn in Southwerk, England to the Cathedral in Canterbury, England is about 60 miles. An average walker can walk 3-5 mile an hour. At that pace, 60 miles could be covered in between from 12 to 20 hours of walking (not chronological hours).
Chaucer's emphasis in The Canterbury Tales is not on the pilgrimage but rather on the tales that are being told and, by extension, on the tale tellers. There is scant information in The Canterbury Tales to let us know the chronological progress of the pilgrimage. If you can't find enough information to keep abreast of the pilgrims' progress, it's because it's not there.
What Chaucer does emphasize though is the qualities, characteristics and class of the tale tellers. One way he does this is through their vocabulary, another way is through their rhetorical style. The upper class speakers, like the knight, have vocabulary distinctions that identify their class, for instance, the use of the word "lady" instead of "wenche." Additionally, Chaucer matches the rhetorical complexity to the class of the speaker, although, some of the tales of the lower class speakers, like the miller and the nun's priest, have surprising rhetorical complexity.
You can read more about this interesting information at Wapedia.com.